A new report from the World Business Council for Sustainable Development (WBCSD), supported by Arup, is calling on the built environment industry to adopt a whole life-cycle approach to assessing the greenhouse gas (GHG) emissions from buildings.
The authors of the report – Net-zero buildings: where do we stand? – estimate that less than 1% of building projects currently calculate and report their full carbon footprint.
The building industry is responsible for 38%, or around 14 gigatons, of all energy-related GHG emissions each year. Global decarbonisation trajectories indicate that the industry needs to reduce these emissions by 50% by 2030 if it is to reach net zero by mid-century and achieve the climate goals of the Paris Agreement.
The report authors claim that the vast majority of buildings currently do not receive an assessment of the carbon footprint across the whole life cycle. The industry has focused on measuring and reducing operational energy use and the carbon associated with it. However, the report highlights the importance of measuring the embodied carbon associated with construction, refurbishment and end of life as part of the building’s whole life-cycle footprint. The report studied six modern buildings and found as much as 50% of the whole life carbon emissions came from embodied carbon.
Using the WBCSD Building System Carbon Framework, the report outlines detailed whole life carbon assessments (WLCA) of six case studies representing what might be considered “best practice” buildings today. Based on these case studies and a discussion of emerging benchmarks in some markets, the authors estimate that by setting explicit targets from the start of a building project and through collaboration along the value chain, emissions could be halved in every building project by 2030.
The six case studies found:
- An average whole life carbon footprint of 1,800 kgCO2e/m2 was estimated across the six case studies.
- As much as 50% of whole life carbon emissions in a building comes from embodied carbon (manufacturing of materials and the construction process) the majority of this being emitted immediately at the start of the life-cycle.
- Typically as few as six materials account for 70% of the construction-related embodied carbon.
The authors of the report recommend some key actions for the industry to take in order to make progress towards a net-zero future:
- Carry out whole life carbon assessments on all projects, using a consistent methodology and open-source sharing of the data obtained
- Develop consistent and transparent carbon intensity data for components, systems and materials used by the industry
- Commit to clear global targets across the buildings industry, including a valid approach to residual emissions (offsetting)
- Adopt a clear definition of a net-zero building, taking into account whole life-cycle carbon
- Achieve wider collaboration as individual organisations taking action is not enough.
Download the report here: arup.com/perspectives/publications/research/section/net-zero-buildings-where-do-we-stand
